Return to the Mystery
by Imagigirl20
Summary: Dipper and Mabel Pines are back with their sister Amanda for another fun-filled summer...only to return and find their great uncles missing. Set off on a quest by a mysterious message from Ford, the Pines siblings are determined to reunite their family. Meanwhile, Stan finds himself in a strange new land and Ford captures a mysterious creature that's not all it appears to be...
1. Chapter 1

**Return to the Mystery**

 **by**

 **Imagigirl20**

 **Hey, guys! I've decided that, by taking on multiple projects at once, I can probably continue writing on a daily basis, yay! I'll let you guys figure out what this next story will be about, okay? (Wink, wink) Enjoy!**

A deer stood by the side of the road chewing on some grass as a green car drove by. It passed a forest full of wildlife and a sign directing it to a town just down the road. A blond girl living in a tent by the sign with her family poked her head out and gasped.

"I don't believe it", she said. "They're back!"

Up the hill, in a large mansion, an old man with a long white beard and dressed in brown overalls stood in the foyer looking out of his telescope. When he saw who occupied the green car, he began jumping around and slapping his knees.

"Tarnation!" he declared. "They're back!"

Giggling wildly, he ran on all fours out to the town. Up on the water tower, a guy with dark hair and wearing a black hoodie spray-painted a heart with a message: W.C.+R.V. 4 EVR. He turned to see the green car driving into town and groaned.

"Oh, great", he said.

A woman with one eye shut served coffee in the diner in town. When she saw the green car, she dropped the coffee pot on the ground.

"Oh, they're back!" she said, and ran outside.

"They're back!" said a guy wearing a white tank top and cowboy boots. He cried out as he slipped on the spilled coffee and fell.

"They're back!" said a rather muscular-looking-and-sounding girl.

"They're back!" said a small Asian girl.

"Oh, sweet", said a girl with long, red hair and wearing a blue and white hat. "They're back!"

As the green car passed through town, the townsfolk lined up on the sidewalk to greet them. It drove through the town, past the woods and into a clearing where there stood a tall, wooden shack surrounded by a bunch of signs. As it came to a halt, a girl with long, curly blond hair pulled into a ponytail gasped.

"Hey, they're back!" she said, running inside.

"Huh?"

A guy behind a cash register and wearing a question mark shirt and a black hat with a tassel ran outside with her to see as the townsfolk came up to the shack.

…

The green car's driver door opened, and a tall girl with a long, brown ponytail wearing a green, camouflage hat, dark green shirt and shorts stepped out.

"We're back", she said.

The two back doors opened, and two kids stepped out. One of them was a boy in a lumberjack's hat, a red shirt, navy vest and brown shorts; the other was a girl with long, brown hair wearing a black skirt and a sweater with a shooting star on it. Followed close behind them was a large pig, who squealed with delight when he saw where he was.

"Hey, Gravity Falls!" said Dipper Pines.

"We're back!" said Mabel Pines.

As the townsfolk cheered, their sister Amanda Pines smiled to herself and got their bags from the trunk.

"Holy Toledo!" said Soos. "Dudes, I feel like it's been, I don't know, two years since I've seen you guys!"

The twins laughed and ran to give the big man a hug.

"Relax, Soos", said Dipper. "It's only been one summer."

"Although admittedly, it _has_ felt like forever since we've been here", said Mabel.

"MABEL!"

Mabel gasped as Candy and Grenda came bursting through the crowd.

"MY GIRLS! AAAAH!"

They all collided together and Grenda picked them both up in a massive hug.

"I missed you so much!" she said.

"Things just were not the same without you", said Candy.

Mabel laughed as Grenda put her and Candy down.

"So, how's Marius doing?"

"Oh, things are great!" said Grenda. "We're in love!" I think."

"Ha-ha, Grenda", said Mabel.

As Dipper was talking to Soos about the Mystery Shack, he felt a tap on his shoulder and turned around.

"Well hey there, stranger", said Wendy.

"Wendy!"

They engaged in a complicated handshake that ended with them switching hats back.

"How's it goin'?" said Dipper.

"Oh, you know, the same", said Wendy. "Still workin' at the Mystery Shack, still undergoing Apocalypse Training with my family; same old, same old."

Just then, Old Man McGucket came bounding up to them, still on all fours.

"Pines twins dos!" he said. "It's great to see y'all again!"

"Hey, McGucket!" said Dipper, chuckling nervously as the man ran circles around them.

"Yo, Dr. Funtimes!"

Dipper turned to see Nate, Lee and Thompson heading for them.

"Hey, guys!"

He fist-pounded each of them.

"Fellow teen friends, hello!" said Mabel.

A goat came up to greet the kids.

"Aww, hey, Gompers!" said Dipper, leaning down to feed him a can. "I saved this on the car ride just for you, buddy."

Amanda slammed the trunk shut and carried Dipper and Mabel's bags to the porch.

"Well, hello there."

"Hmm?"

She turned to see Steve, the leader of the gnomes, staring at her, and she rolled her eyes.

"You had zero chance last summer, and you have less of a chance for this one", she said.

"You need some time to come around", said Steve. "I can respect that."

He snapped his fingers and a herd of gnomes surrounded him, forming into a chair.

"I'll be waiting for you!" he called as he and the gnomes disappeared into the forest.

Amanda shuddered and set the suitcases inside the shack before joining her brother and sister outside.

"So where are Grunkle Stan and Ford?" said Mabel.

"Yeah, I still have so many questions for Ford", said Dipper.

Soos's face fell.

"Uh, dudes...we haven't heard anything from your uncles since they left on their boating trip."

Amanda and the twins gasped.

"It's been nine months", said Dipper. "Where could they be?"

"I might have an idea!"

The Pines twins turned to see Lil Gideon accompanied by Ghost Eyes heading towards them.

"Gideon?"

"Dipper, Mabel! So nice to see y'all again."

The twins sighed.

"Hey, Gideon", they said simultaneously.

"What's this about you knowing where Stan and Ford are?" said Amanda.

"Well, it's the strangest thing, actually", said Gideon. "Ghost Eyes and I were in the park, uh…havin' a picnic with the rest of the gang when all of a sudden, there was this giant flash of light, and a portal ripped open right in front of us!"

Gideon snapped his fingers, and Ghost Eyes pulled a bottle out of his jacket.

"This fell out before the thing sealed up again."

Ghost Eyes handed it to Amanda, who stared at a rolled up piece of paper inside.

"Really?" she said. "A message in a bottle; could this _be_ any more cliche?"

Without another word, she pulled out the cork with her bare hands as everyone stared at her.

"What? I have strong fingers, okay?"

Carefully, she pulled out the message and handed it to Dipper, who opened it and began to read:

" _Our suspicions have been confirmed; Gravity Falls was just the pinnacle of the source of anomalies surrounding this country. Stanley and I have encountered many strange and wondrous creatures, but none as strange as what we have come to name The Butterfly, a strange, human-like creature that would tear a hole in space and fly through another hole just like it, its destination unknown. This strange occurrence happened every night throughout all of September when suddenly, it stopped. We didn't see the creature for some time after that, but then the strangest thing happened: We saw another one, just like it, except...older. It appeared to be injured. Curious to see where it was going, Stanley and I devised a way to follow it through the portal it created."_

Dipper gulped.

" _But something went wrong: The first creature's portals started re-opening and sucking everything into its abyss. Stanley and I were separated when he was sucked away into one of the portals. They have since closed and have not reopened, so I have no way of knowing where he is. All I can hope is that he didn't wind up in the Nightmare Realm. I'm writing this to anyone willing to come to our rescue. The last known location of our boat, the Stan O'War II, is Latitude 25.0000 degrees North; Longitude 71.0000 degrees West. Find us; help us; save us, if you can."_

 _-Stanford Pines_

 _October 31_

"Latitude 25.0000 degrees North, Longitude 71.0000 degrees West?" said Dipper, putting the note down. "Where _is_ that?"

Amanda examined the note, and her eyes went wide.

"Dipper, Mabel: That's the Bermuda Triangle."

…

Stanley Pines opened his eyes and found himself in a weird-looking forest. He got up and brushed himself off.

"Man", he said, "that was one crazy storm, huh, Ford?"

His deep, scratchy voice echoed around him.

"Whoa, what the-?"

Stanley examined his surroundings, but there was no sign of his brother.

"Stanford?! Oh no, not again…"

Stanley ran to the edge of the forest.

"Ford?! Come on where are ya?"

He gasped as he came out of the forest and was faced with a little village that seemed to be devoid of any technology.

"Whoa, what's goin' on?"

Stanley looked up to see a giant castle just past the village.

"Where the heck am I?!"

…

Stanford Pines braved the thunder and lightning and stood on the deck of the ship, his handheld scanner searching the sky.

"Oh, where the heck is he?" he said, searching the machine for any readings.

Suddenly, a portal ripped open in the night sky and a human-like butterfly creature flew through.

"Aha!"

Ford grabbed a rope and began to spin it.

" _This time,_ I've got you...hyah!"

He tossed the rope and it looped around the creature's foot.

"Haha, yes! Now, to secure the beast."

He quickly tied the rope to the ship's mast using a sailor's knot. The creature was suddenly pulled back. Sensing it was trapped, the creature pumped its wings harder and faster, trying to get away. The boat threatened to lift out of the sea!

"Oh no, you don't!"

Ford threw another rope, this one securing itself around the creature's waist.

"You're gonna help me find out what happened to my brother, you-!"

The creature kicked its arms and legs, still trying to get away, but it was no use. Ford used his strong arms to haul the creature in, careful not to get knocked overboard by its bright yellow wings. Ford was quick to tie the creature around the mast, double-knotting the rope and keeping it secure. To his surprise, the creature stopped moving and was calm, a smile plastered on its face.

"What _is_ this thing?" said Ford. "I've never seen anything quite like it."

Suddenly, the creature closed its eyes and Ford was blinded by a bright, golden light, causing him to shield his eyes. When it cleared, gone was the creature with six arms and yellow wings. Tied to the mast in front of him now was a girl with long, blond hair and a thorny headband.

"What the-where _am_ I?!"

She saw Ford staring at her with his mouth open.

"Oh, hey", she said, chuckling sheepishly. "Whassup?"

…

Amanda grunted as she shoved the suitcases back into the car.

"Unbelievable", she muttered to herself as she slammed the lid of the trunk. "I swear to goodness, if we somehow get some sort of retraction to this adventure, these kids can build some muscle and lift their _own_ suitcases."

She sighed and wiped her hands on her shorts.

"Alright, saddle up!" she announced. "All shore who's _going_ ashore, and all that."

"Dude, you do realize you're gonna have to lift the suitcases again once you get to the dock, right?" said Dipper.

Amanda's eyes turned into slits.

"Getting in the car!"

Dipper quickly hopped in the backseat and buckled his seatbelt securely. Amanda smiled and nodded.

"Let's go, Mabel!" she said. "We need to head out before sundown."

"Coming!"

Mabel came rushing down the stairs with another suitcase. Amanda watched as some pink powder fell out.

"Oh, no", she said. "No Smile Dip, EVER! Don't you remember what you and Dipper told me happened _last time_ you ate that stuff?"

Mabel flashed back to the horrific experience she had at the haunted convenience store. With a smile, she dumped the bag's contents out on the lawn. Amanda nodded at Ghost Eyes, who poured gasoline on it. Soos struck a match and tossed it onto the sugary candy, hypnotized by the bright-colored flames.

"Those colors", he muttered, "they burn so beautifully!"

"Ooh!"

The townsfolk joined in, also spellbound.

"Aaaand this just got weird", said Amanda.

"I sure wish you could come with us, Soos", said Dipper.

"Yeah", said Mabel, "it won't really feel like an adventure without you."

"Aww", said Soos. "That's sweet, dudes. But I have a business to run now, and a lady to provide for."

"Speaking of which, Soos", said Melanie, "the 6:30 tour group has arrived."

Soos straightened his hat.

"Gotta go, guys", he said, heading back towards the shack. "Have fun in the Bermuda Triangle!"

"I think the more accurate term would be, try to _survive_ the Bermuda Triangle", Amanda said, shaking her head.

With her twin siblings loaded, she got in the car and drove towards the docks.

"Don't worry, guys!" Mabel called out the window. "We'll be back with the first set of Pines twins in _no_ time!"

Amanda drove them down to the marina, where Old Man McGucket stood waving his hat.

"Ahoy, Pines!" he called, laughing wildly.

Amanda leaned down.

"Remind me again why we're letting the hillbilly tag along?" she said through her smiling teeth.

"Because he's a friend of Ford's who wants to help, and he's the richest man in Gravity Falls with a boat", said Dipper with the same expression on his face.

"Of course he is."

Amanda straightened up and started dragging the luggage up the ramp. Mabel stared out past the sea.

"Hey, it's okay", said Dipper, putting a reassuring hand on his sister's shoulder. "We're gonna find them both."

Mabel sighed.

"I hope you're right."

With that said, the twins followed their older sister onto the ship.

"Cast off!" said McGucket. "Trim that sail! Swipe the poop deck! Hard to starburst!"

"It's starBOARD", said Amanda, shaking her head. "Have you ever sailed before?"

McGucket shrugged and Amanda sighed.

"Alright, move over: I'm the captain of this ship now."

McGucket stepped to the side and Amanda took her place at the wheel.

"Amanda, since when do you know how to steer a sailboat, let alone captain it?" said Dipper.

"There's lot of things you don't know about me, Dipper", said Amanda, her eye on the horizon. "Lots. Of. Things. Mabel! Cut the lines!"

"Aye-aye, Captain!"

Mabel held Waddles up to the ropes tying the ship to the dock, and the pig chomped them up.

"Dipper, raise the sail!"

"Uh, Amanda? You do know this boat has a motor, right?"

"Oh, right. Well, then...everyone to the front!"

McGucket, Dipper and Mabel stood at the ship's stern and stared out at the open water.

"Avast, mateys", said Amanda. "There be no turnin' back now."

"Were you speaking like a pirate just now?" said Mabel, one eyebrow raised.

"Yes; yes, I was."

The twins shrugged and continued to stare at the sea as they sailed off towards the ocean.

 **So, if no one has figured it out by now, I have decided to crossover Gravity Falls and Star vs. The Forces of Evil! Why? Because I really like these shows and I CAN! Anyway, let me know if you think this is a good idea, or if I should scrap this fanfic and move on. Thanks for reading, see you soon!**

 **-Imagigirl20**


	2. Chapter 2

**Return to the Mystery**

 **Chapter 2**

 **No new reviews, nothing to say. On with the show.**

 **Disclaimer: I own nothing pertaining to Gravity Falls/Star vs. the Forces of Evil.**

Amanda Pines shielded her eyes from the setting sun as she stood at the wheel of Fiddleford McGucket's motor boat. She stared down at the compass in her left hand and made sure they were headed in the right direction.

"Yee-haw!" said McGucket. "How nice! You brought me a metal cookie-jiggama-whatsit!"

"No, Mr. McGucket, it's not a-"

But she was cut off as McGucket swiped it from her hand and tried to bite into it.

"Sweet hootenanny", he said, "the durn thing doesn't wanna go in my mouth."

"Now I know how that guy with a hand protruding from his head felt", said Dipper.

"The what?" said Mabel.

"Nothing!"

As the sun set on the ocean, Amanda heard a clap of thunder and looked up to see dark clouds forming in the atmosphere. She sucked the tip of her finger and stuck it in the air, checking the wind's direction, but there wasn't any.

"Hmm", she said, "I'd say this is impossible, but I've seen weirder things."

BAM! Amanda and the twins looked up to see orange lightning light up the night sky.

"Is it just me, or did it get real dark real fast?" said Mabel, stroking the ends of her hair nervously.

"Great Uncle Ford was right", said Dipper. "There _are_ strange occurrences outside of Gravity Falls."

"Htoum ym edisni teg!" they heard a voice say.

"Huh?" Amanda and the twins said simultaneously.

"RUN FOR YOUR LILLY-PICKIN' LIVES!"

McGucket suddenly ran past them on all fours, heading below deck. The twins turned around and gasped.

"Uh, Amanda?" Dipper said nervously, pointing at the water behind them.

"What is it?"

Amanda turned around and her jaw dropped. A creature with the head of a bull and body of a large water snake had risen out of the sea.

"UOY TAE OT TNAW I!" it roared.

Amanda and the twins screamed, and Amanda jammed her fist down on the Autopilot button.

"Our course is still set", she said. "Get below deck, NOW!"

Dipper and Mabel did as they were told while Amanda ran to the supply box. She yanked open the hatch and a raccoon jumped out, causing her to back away and scream. She groaned.

"Seriously?" she said, and stuck her head back in.

Amanda rifled through a whole bunch of things: Life jackets, flashlights, broken banjo strings...and a flare gun.

"Yes!"

She grabbed it and tucked it into her shorts pocket as another bolt of lightning struck the sea. The creature roared behind the boat, continuing to pursue them.

"Ylleb ym ni efas eb lluoy noos!" it roared.

"Never thought I'd actually have the chance to use one of these things", said Amanda, and held the gun in her hand.

Everything seemed to move in slow motion: Amanda watched the creature as it got closer to the boat; Dipper and Mabel observed from the window below deck as lightning continued flashing in the sky; McGucket clutched the raccoon to his body and cowered in terror.

Amanda raised the flare gun so it was eye-to-eye with the sea creature.

"Uoy tae ot em wolla!" it growled.

Amanda's eyes drifted to the sky where she saw lightning flash behind the clouds.

"Almost...almost...NOW!"

Amanda pulled the trigger and the flare was shot out. She dropped the gun and ran, throwing herself on the deck.

"BRACE YOURSELVES!" she called down to Dipper and Mabel, who covered their heads.

BAM! Lightning struck, igniting the flare and hitting the beast directly in the face. The monster let out a horrendous cry and sank beneath the waves as the boat was rocked from the sudden impact. Finally, it settled back on the ocean. Amanda breathed a sigh of relief and got up, dusting herself off as the twins came back on deck.

"What _was_ that thing?" said Mabel.

"I'd rather not stick around to find out", said Dipper.

"Agreed", said Amanda. "We've got a long way to go; let's hope we don't run into anything else."

…

"Sooo you gonna untie me, or are we just gonna, like, STARE at each other or whatever?"

Stanford Pines stood staring at the blond-haired girl he had tied to the mast of the ship. Finally, he shook his head.

"What-who _are_ you?"

"I'm Star, Star Butterfly", said the girl. "I'm a princess...although, not really...kind of a, uh...complicated story there-"

"But how did you come to be here?" said Ford. "What was that creature I saw in the sky? How are all these portals being opened? What happened to-"

"WHOA, okay, WAAAAAY too many questions, Gramps", said Star. "Could we maybe, uh...get these ropes undone before I start answerin' your junk, 'kay?"

"Huh? Oh...yes, of course."

Ford withdrew a knife and cut her loose. Star dropped to the deck flat on her face and Ford immediately helped her up.

"My apologies, your...uh, highness?"

"No harm done!" said Star, accepting his hand. "Now, who are _you_?"

"My name is Stanford Pines", said Ford.

"Stanford", said Star. "Staaaaaan-ferrrrrd….I like it, it sounds so old-timey! Kind of adorable."

"Uh, thanks?" said Ford. "Ms. Butterfly-"

"Oh, please, dude! Call me Star!"

"Uh, Ms. Star, where did you come from?"

"Pfft! From that little hole in the sky!" said Star, pointing up to the portal she had flown through.

Ford blinked at her.

"Ohhhh, you meant originally. Got it, got it."

Star cleared her throat.

"I am from the magical dimension of Mewni!"

"Strange", said Ford. "I've visited many dimensions in my time, but I have never heard of this-"Mewni" you speak of."

"Oh, well, it's pretty great", said Star, giggling. "Not _too_ great now that I've discovered my whole family history is a sham and I might just be a lame little servant girl...but yeah, still a nice place to live. And you don't even have to worry about the monsters anymore!"

"Monsters?!"

"Oh, yeah, they were all over the place. But they're totally cool now. Me and my friends Marco and PonyHead had a totally off-the-hook party with them, and now we're all buddies!"

"Interesting", said Ford, taking notes in his journal.

Then, he shook his head.

"What am I doing?" he said to himself, and turned to Star. "I have to find Stanley and figure out a way to shut these portals!"

"Oh, I can do that!" said Star.

She went to pull out her wand, only to realize it wasn't there.

"Ohhh right...I gave it to Eclipsa", she muttered. "That, uh...that might have been a mistake…"

"You gave what to _who_ now?" said Ford, raising an eyebrow in confusion.

"Yeah, he-he, my bad!" said Star. "See, I used to have this magic wand which let me cast spells and junk, but now it's in the hands of someone who could potentially be bad...you know, 'cause she married a monster and is currently raising a monster baby."

"She's making less sense than Fiddleford", Ford thought, "but she may be the only link I have to finding out what happened to Stanley."

"Hey, I know!" said Star. "I'll just fly back to Mewni, ask Eclipsa if I can _borrow_ the wand, and seal those portals closed! By the way, who's Stanley?"

"Stanley Pines is my twin brother. The two of us were investigating anomalies in the Bermuda Triangle when you came flying through your portals and separated us. I have no idea where he went."

"Oh, my gosh", said Star, tears welling in her eyes. "I am so sorry-I never meant to separate you from your brother!"

"What are you even doing out here?" said Ford. "If Mewni's so great, why would you ever want to leave it?"

"Well...I sort of can't help it", said Star, sitting down and bringing her knees to her chest. "You see, I have this sort of...condition called sleep-spelling. When it happens, I start opening portals to other dimensions while I'm dreamin'."

"That would explain why Stanley and I could only see you at night. But how is this possible?"

"It's magic, dawg!" said Star. "Truthfully, I'm glad you woke me up when you did. If I had flown any farther, I might have wound up in-"

She brought her mouth close to Ford's ear.

"The Void", she whispered dramatically.

Ford scratched his head.

"And before you ask about it, you do NOT want to know about that jacked-up place", said Star, waving her hand dismissively. "All you need to know is that if you stay in there too long, you forget who you are...AND YOU NEVER WANNA LEAVE."

Ford yelped in surprise, hoping Stanley hadn't wound up there. Then, he cleared his throat.

"It would seem I'm in need of assistance", he said. "I sent for help a while back, but I have no way of knowing if my message reached anyone from back home or not."

"Sooo you need MY help?" said Star, and Ford nodded.

"You may be my only hope."

 **Hey, guys. Sorry to cut this kind of short, but at this point I can't think of anything else; I'm so tired, I feel like my head's on BACKWARDS. Also, I feel a MONSTER headache coming on. Until next time!**

 **-Imagigirl20**

 ***20-8-5 13-15-14-19-20-5-18 18-15-1-18-19 13-5-1-14 19-15-13-5-20-8-9-14-7.**

 **10-21-19-20 19-1-25 20-8-5-13 2-1-3-11-23-1-18-4-19!**


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